You can open or create artwork and use this artwork as a fill pattern for objects or even text. Fill patterns can be created from line art, but also from pixel images.
How to create a fill pattern
    1. Select the object(s) you want to use as pattern and click Extra > Create Pattern.
    2. Click Window > Color to display the Color panel.
    3. The pattern you created in step 1 is added to the Color panel (A).
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    4. Click Window > Color List.
    5. Point to the pattern in the Color panel and drag it to the Color List.
        The pattern can be applied to objects by drag & drop.
    6. Click the menu button and select Save.